Introduction
An arc flash study is a crucial part of any electrical safety program. It is required by the National Fire Protection Association (NFPA) 70E standard for assessing the risk of arc flash hazards and determining the appropriate safety measures to protect workers.
An arc flash study involves several steps, including conducting an arc flash analysis, developing protective plans, and implementing safety measures. The five key ingredients for a successful arc flash study are discussed in this article.
1. Comprehensive Data Collection: The first step in conducting an arc flash study is to gather comprehensive data about the electrical system from the available sources. It includes gathering of drawings, conductor information including size and length, overcurrent protective device information (i.e. fuses and breakers), transformer characteristics, etc. Data must be accurate and complete to ensure the analysis is precise, and the calculations are appropriate.
2. Accurate and Thorough Analysis: After collecting comprehensive data, a licensed professional electrical engineer should perform an accurate and thorough arc flash analysis. The analysis should include such things as equipment short-circuit current, available fault current, protective device characteristics, and the time-current coordination of the protective devices. The analysis will consider the arc flash energy levels at each point of the system and determine the safety procedures and PPE required to protect workers.
3. Safety Plan Development: A safety plan should be developed. The safety plan will specify how to protect workers from arc flash hazards, ensuring safety procedures and the appropriate PPE are in place. It will also describe warning labels, equipment markings, and any precautions to be taken when working on or near the equipment.
4. Training and Implementation: After the safety plan is developed, employees must be trained on the plan and how to follow the safety procedures. It includes conducting safety meetings, job planning, and review of procedures. All relevant employees should be instructed on the potential hazards of arc flash, the safety measures necessary to manage them, and the importance of using PPE. Once trained, the safety plan must be strictly followed to ensure the safety of all workers.
5. Regular Review and Update: Electrical systems are subject to changes that may affect their ability to safely function. The safety plan should be periodically reviewed and updated to reflect changes in the system. The review may include adding or removing equipment, changes to the electrical load, new protective devices, or modifications to the system’s protective settings. A regular review will ensure that the protective measures remain effective and workers are adequately protected. In conclusion, a successful arc flash study involves comprehensive data collection, accurate and thorough analysis, safety plan development, training and implementation, and regular review and update. Implementing these key ingredients will help mitigate the risk of arc flash hazards, ensuring the safety of workers while working on or near electrical systems.